1. Field of the Invention
This invention relates to new and useful improvements in a breast prosthesis suitable for implantation in a human breast for reconstructive or cosmetic purposes.
2. Brief Description of the Prior Art
Surgical reconstruction of human breasts as a result of injury or as a result of partial or total mastectomy has been performed for many years. In recent years, surgical augmentation of breasts has particularly become common for cosmetic purposes in cases of breast hypoplasia. Over the past 10-15 years, various surgical prostheses have been developed for implantation in the human breast as a part of breast reconstruction or augmentation. Recently developed prostheses have been satisfactory in some cases but in a substantial number of other cases significant degrees of capsular tightness or contracture has developed causing undesirable appearance associated with some pain and discomfort.
Surgical procedures for breast reconstruction are described in detail in the medical literature, particularly in Journals dealing with plastic surgery. Some of this literature describes prosthethic devices which are in common use. The recently published textbook RECONSTRUCTIVE PLASTIC SURGERY, CONVERSE, 1980, pp. 3694-3704 gives a thorough review of the history of the development of breast prostheses and of the problems involved. PLASTIC SURGERY, WILLIAM C. GRABB AND JAMES W. SMITH, 1979 is another text giving a thorough treatment of this subject. Representative medical journal references, listed somewhat in order of relevance and importance, are: PLASTIC AND RECONSTRUCTIVE SURGERY, December 1976, pp. 689-693; August 1972, pp. 107-113; November 1976, pp. 555-560; August 1976, pp. 137-141; January 1980, pp. 30-33; November 1977, pp. 720-724; August 1979, pp. 151-155; July 1980, pp. 71-73; June 1977, pp. 849-850; March 1980, pp. 302-306; and AESTHETIC PLASTIC SURGERY, 1979, 3:339-341; 1978, 2:435-441; and 1978, 2:217-234.
Most of the prior art on the physical structure of breast prostheses, however, is found in the patent literature, particularly the U.S. patents relating to that subject. The patent literature includes many experimental and non-commercial prostheses as well as ones which have had substantial medical usage. The following patents represent a summary of the most pertinent patent art dealing with breast prostheses.
Cronin U.S. Pat. No. 3,293,663 discloses a breast prosthesis comprising a flexible container filled with a soft gel and a corrugated fabric attached to one side of the container so that tissue can grow through the fabric to anchor the container to the chest wall. This patent is probably the earliest example of a medically acceptable prosthesis which has been commercially produced for many years. However, as noted elsewhere, this prosthesis has been subsequently found to be the focal point of a serious problem, viz. the formation of a tight fibrous capsule which contracts and causes the prosthesis to become hard and painful.
Hartley U.S. Pat. No. 3,934,274 discloses a deflatable breast prosthesis comprising a pair of bags or sacs, one inside the other, filled with liquid. The outer bag is provided with a flap valve through which fluid can be added or removed to adjust the amount of fill. This patent illustrates an attempt to design a prosthesis which could overcome the problem of capsular contracture. However, this prosthesis has been used only to a limited extent and the procedure for softening the prosthesis by removal of fluid through the flap valve has not proved to be technically successful and has been largely abandoned.
A number of U.S. patents disclose various proposed breast prostheses which do not appear to have had general acceptance in the medical literature. These patents may possibly represent experimental devices which have not been accepted for commercial development and usage by the manufacturers of such equipment.
A series of patents to Pangman, starting prior to the Cronin patent, disclose some designs for breast prostheses which do not seem to be in current use. Pangman U.S. Pat. No. 2,842,775 discloses a surgically implantable breast prosthesis for use in surgical reconstruction having an outer layer of sponge material and an inner sac filled with a fluid. Pangman U.S. Pat. No. 3,366,975 discloses a breast prosthesis with a core of plastic foam surrounded by a membrane impervious to fluids and, in turn, covered by a porous layer to which human tissue can adhere. Pangman U.S. Pat. No. 3,559,214 discloses a breast prosthesis for surgical implantation which is hollow and filled with a soft fluid gel but is subdivided into a plurality of compartments. Pangman U.S. Pat. No. 3,683,424 discloses a breast prosthesis for surgical implantation which has an elastic sac containing a foam core and a liquid in the pores thereof and having a tube for adjusting the extent of fill of the implant.
Several U.S. patents disclose various prostheses having fluid or plastic fillers and, in some cases, having means for adjusting the size or extent of fill. These devices do not appear to be available from any commercial source and are assumed to be experimental or prototypes, e.g. Boone U.S. Pat. No. 3,600,718; Mohl et al U.S. Pat. No. 3,663,968; Perras et al U.S. Pat. No. 3,665,520; Perras U.S. Pat. No. 3,681,787; McGhan et al U.S. Pat. No. 3,852,832; Koneke et al U.S. Pat. No. 3,852,833; Lynch U.S. Pat. No. 3,883,902; Sanders et al U.S. Pat. No. 3,919,724; and Lynch U.S. Pat. No. 3,986,213.
Cresswall U.S. Pat. No. 4,035,850 discloses a method and apparatus for insertion of a soft prosthesis through an incision into a human body.
In considering the prior art on breast prostheses, it is necessary to keep in mind the difference between surgically implanted prostheses and external prosthetic devices. The patent literature has numerous examples of external devices which have little or no relevance to surgically implanted prostheses, e.g. Bernhardt U.S. Pat. No. 2,542,619; Kausch U.S. Pat. No. 2,543,499; Freedman U.S. Pat. No. 2,636,182; and Mann U.S. Pat. No. 3,619,819.